Public bug reported: I have a network which supports jumbo frames end-to-end internally. This weekend, after rebooting my laptop, it came up only negotiating 100mbps, but networkManager still set the MTU to 9000, which doesn't work (can't do jumbo frames on anything except 1gbps, by spec). NM should recognie the auto-negotiated rate as part of the "automatic MTU" determiniation.
Kubuntu 14.04. When I pulled the cable, and rerouted it, the laptop re- negotiated 1gbps again, and jumbo frames went fine. This output was gathered during the time when the laptop was stuck at 100mbps. rob@kubuntu4:~$ lsb_release -rd Description: Ubuntu 14.04 LTS Release: 14.04 rob@kubuntu4:~$ sudo apt-cache policy network-manager [sudo] password for rob: network-manager: Installed: 0.9.8.8-0ubuntu7 Candidate: 0.9.8.8-0ubuntu7 Version table: *** 0.9.8.8-0ubuntu7 0 500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages 100 /var/lib/dpkg/status Network setup is: kubuntu laptop -> dlink switch -> ESXi 5.1 server -> VMs MTU=9000 causes problems. VM -> VM works on same server. Switch hardware: http://www.dlink.com/us/en/business-solutions/switching/unmanaged-switches/rackmount/dgs-1024d-24-port-copper-gigabit-switch ESX set up following: http://www.edge-cloud.net/2013/11/jumbo-frames-vmware-esxi/ TCP packets over 1500 bytes just keep getting retransmitted, accordint to tcpdump captures. Laptop: rob@kubuntu4:/var/log$ sudo ethtool eth0 [sudo] password for rob: Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Speed: 100Mb/s Duplex: Full Port: Twisted Pair PHYAD: 2 Transceiver: internal Auto-negotiation: on MDI-X: off (auto) Supports Wake-on: pumbg Wake-on: g Current message level: 0x00000007 (7) drv probe link Link detected: yes rob@kubuntu4:/var/log$ ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:21:cc:cf:e0:78 inet addr:192.168.0.106 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::221:ccff:fecf:e078/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:9000 Metric:1 RX packets:17744 errors:0 dropped:0 overruns:0 frame:0 TX packets:15941 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:11750951 (11.7 MB) TX bytes:5220060 (5.2 MB) Interrupt:20 Memory:d2500000-d2520000 VM SSH Server: rob@srv1:/var/log$ sudo ethtool eth0 [8/1084] [sudo] password for rob: Settings for eth0: Supported ports: [ TP ] Supported link modes: 1000baseT/Full 10000baseT/Full Supported pause frame use: No Supports auto-negotiation: No Advertised link modes: Not reported Advertised pause frame use: No Advertised auto-negotiation: No Speed: 10000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 0 Transceiver: internal Auto-negotiation: off MDI-X: Unknown Supports Wake-on: uag Wake-on: d Link detected: yes rob@srv1:/var/log$ ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:50:56:B6:7F:3D inet addr:192.168.0.21 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::250:56ff:feb6:7f3d/64 Scope:Link UP BROADCAST RUNNING ALLMULTI MULTICAST MTU:9000 Metric:1 RX packets:22817347 errors:0 dropped:80 overruns:0 frame:0 TX packets:11956945 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:11504454844 (10.7 GiB) TX bytes:32510875048 (30.2 GiB) ESX Server: This system has been migrated to ESXi 5.1.0. ~ # esxcfg-vswitch -l Switch Name Num Ports Used Ports Configured Ports MTU Uplinks vSwitch0 128 24 128 9000 vmnic0,vmnic1 PortGroup Name VLAN ID Used Ports Uplinks Management Network 0 1 vmnic0,vmnic1 VM Network 0 17 vmnic0,vmnic1 VMkernel 0 1 vmnic0,vmnic1 ~ # esxcfg-vmknic -l Interface Port Group/DVPort IP Family IP Address Netmask Broadcast MAC Address MTU TSO MSS Enabled Type vmk0 VMkernel IPv4 192.168.0.251 255.255.255.0 192.168.0.255 00:50:56:71:b6:3a 9000 65535 true STATIC vmk1 Management Network IPv4 192.168.0.250 255.255.255.0 192.168.0.255 00:50:56:47:fc:b9 9000 65535 true STATIC ~ # esxcfg-nics -l Name PCI Driver Link Speed Duplex MAC Address MTU Description vmnic0 0000:03:00.00 bnx2 Up 1000Mbps Full 00:1e:4f:1f:fa:6c 9000 Broadcom Corporation Broadcom NetXtreme II BCM5708 1000Base-T vmnic1 0000:07:00.00 bnx2 Up 1000Mbps Full 00:1e:4f:1f:fa:6e 9000 Broadcom Corporation Broadcom NetXtreme II BCM5708 1000Base-T ** Affects: network-manager (Ubuntu) Importance: Undecided Status: New ** Tags: frames jumbo mtu -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1324214 Title: NetworkManager sets MTU to 9000 even on 100mbps connections To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1324214/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs